package com.oner365.data.commons.util;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.security.SecureRandom;
import java.util.Arrays;
import java.util.Random;
import javax.imageio.ImageIO;

/**
 * 验证码工具类
 *
 * @author zhaoyong
 */
public class VerifyCodeUtils {

    /**
     * 使用到Algerian字体，系统里没有的话需要安装字体，字体只显示大写，去掉了1,0,i,o几个容易混淆的字符
     */
    public static final String VERIFY_CODES = "123456789ABCDEFGHJKLMNPQRSTUVWXYZ";

    private static final Random RANDOM = new SecureRandom();

    private static final int COLOR_20 = 20;

    private static final int COLOR_255 = 255;

    private static final int RGB_LENGTH = 3;

    /**
     * Generate constructor
     */
    private VerifyCodeUtils() {
    }

    /**
     * 使用系统默认字符源生成验证码
     * @param verifySize 验证码长度
     * @return String
     */
    public static String generateVerifyCode(int verifySize) {
        return generateVerifyCode(verifySize, VERIFY_CODES);
    }

    /**
     * 使用指定源生成验证码
     * @param verifySize 验证码长度
     * @param sources 验证码字符源
     * @return String
     */
    public static String generateVerifyCode(int verifySize, String sources) {
        if (sources == null || sources.length() == 0) {
            sources = VERIFY_CODES;
        }
        int codesLen = sources.length();
        SecureRandom random = new SecureRandom();
        random.nextBytes(new byte[sources.length()]);
        StringBuilder verifyCode = new StringBuilder(verifySize);
        for (int i = 0; i < verifySize; i++) {
            verifyCode.append(sources.charAt(random.nextInt(codesLen - 1)));
        }
        return verifyCode.toString();
    }

    /**
     * 输出指定验证码图片流
     * @param w 宽度
     * @param h 高度
     * @param os 输出流
     * @param code 验证码
     * @throws IOException 异常
     */
    public static void outputImage(int w, int h, OutputStream os, String code) throws IOException {
        int verifySize = code.length();
        BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
        Graphics2D g2 = image.createGraphics();
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
        Color[] colors = new Color[5];
        Color[] colorSpaces = new Color[] { Color.WHITE, Color.CYAN, Color.GRAY, Color.LIGHT_GRAY, Color.MAGENTA,
                Color.ORANGE, Color.PINK, Color.YELLOW };
        float[] fractions = new float[colors.length];
        for (int i = 0; i < colors.length; i++) {
            colors[i] = colorSpaces[RANDOM.nextInt(colorSpaces.length)];
            fractions[i] = RANDOM.nextFloat();
        }
        Arrays.sort(fractions);

        // 设置边框色
        g2.setColor(Color.GRAY);
        g2.fillRect(0, 0, w, h);

        Color c = getRandColor(200, 250);
        // 设置背景色
        g2.setColor(c);
        g2.fillRect(0, 2, w, h - 4);

        // 绘制干扰线 设置线条的颜色
        g2.setColor(getRandColor(160, 200));
        for (int i = 0; i < COLOR_20; i++) {
            int x = RANDOM.nextInt(w - 1);
            int y = RANDOM.nextInt(h - 1);
            int xl = RANDOM.nextInt(6) + 1;
            int yl = RANDOM.nextInt(12) + 1;
            g2.drawLine(x, y, x + xl + 40, y + yl + COLOR_20);
        }

        // 添加噪点 噪声率
        float yapRate = 0.05f;
        int area = (int) (yapRate * w * h);
        for (int i = 0; i < area; i++) {
            int x = RANDOM.nextInt(w);
            int y = RANDOM.nextInt(h);
            int rgb = getRandomIntColor();
            image.setRGB(x, y, rgb);
        }

        // 使图片扭曲
        shear(g2, w, h, c);

        g2.setColor(getRandColor(100, 160));
        int fontSize = h - 4;
        Font font = new Font("Algerian", Font.ITALIC, fontSize);
        g2.setFont(font);
        char[] chars = code.toCharArray();
        for (int i = 0; i < verifySize; i++) {
            AffineTransform affine = new AffineTransform();
            affine.setToRotation(Math.PI / 4 * RANDOM.nextDouble() * (RANDOM.nextBoolean() ? 1 : -1),
                    ((float) w / verifySize) * i + fontSize / 2d, h / 2d);
            g2.setTransform(affine);
            g2.drawChars(chars, i, 1, ((w - 10) / verifySize) * i + 5, h / 2 + fontSize / 2 - 10);
        }

        g2.dispose();
        ImageIO.write(image, "jpg", os);
    }

    private static Color getRandColor(int fc, int bc) {
        if (fc > COLOR_255) {
            fc = COLOR_255;
        }
        if (bc > COLOR_255) {
            bc = COLOR_255;
        }
        int r = fc + RANDOM.nextInt(bc - fc);
        int g = fc + RANDOM.nextInt(bc - fc);
        int b = fc + RANDOM.nextInt(bc - fc);
        return new Color(r, g, b);
    }

    private static int getRandomIntColor() {
        int[] rgb = getRandomRgb();
        int color = 0;
        for (int c : rgb) {
            color = color << 8;
            color = color | c;
        }
        return color;
    }

    private static int[] getRandomRgb() {
        int[] rgb = new int[RGB_LENGTH];
        for (int i = 0; i < RGB_LENGTH; i++) {
            rgb[i] = RANDOM.nextInt(COLOR_255);
        }
        return rgb;
    }

    private static void shear(Graphics g, int w1, int h1, Color color) {
        shearX(g, w1, h1, color);
        shearY(g, w1, h1, color);
    }

    private static void shearX(Graphics g, int w1, int h1, Color color) {

        int period = RANDOM.nextInt(2);

        int frames = 1;
        int phase = RANDOM.nextInt(2);

        for (int i = 0; i < h1; i++) {
            double d = (period >> 1) * Math.sin((double) i / period + (6.2831853071795862D * phase) / frames);
            g.copyArea(0, i, w1, 1, (int) d, 0);
            g.setColor(color);
            g.drawLine((int) d, i, 0, i);
            g.drawLine((int) d + w1, i, w1, i);
        }

    }

    private static void shearY(Graphics g, int w1, int h1, Color color) {

        int period = RANDOM.nextInt(40) + 10;

        int phase = 7;
        for (int i = 0; i < w1; i++) {
            double d = (period >> 1) * Math.sin((double) i / period + (6.2831853071795862D * phase) / COLOR_20);
            g.copyArea(i, 0, 1, h1, 0, (int) d);
            g.setColor(color);
            g.drawLine(i, (int) d, i, 0);
            g.drawLine(i, (int) d + h1, i, h1);

        }
    }

}
